Toxicology : Poisons and Alcohol

to Arsenious Acid. By Dr. Yon Specz, Professor of Chemistry in the Theresian Academy of Vienna. In the year 1834, as our readers are aware, Dr. R. W. Bunsen and Dr. A. A. Berthold published a small work at Gottingen, on the use of hydrated per-oxyde of iron as an antidote to arsenic, in which they claimed for this remedy all the proEerties of a true specific. With the view of testing the accuracy of their results, > . Von Specz prepared a large quantity of the hydrated peroxyde of iron, and instituted a series of experiments with it, on animals. Experiment 1. On the 5th of October, 1834, at ten o'clock in the forenoon, twelve grains of white arsenic, mixed with a portion of boiled meat, was adminis-

" All substances are poisons. There is none which is not. The right dose differentiates a poison and remedy." -Paracelsus (1495-Paracelsus ( -1541,

Swiss physician and chemist
Poison hemlock is not an evergreen tree, but a plant related to the carrot. It contains an alkoloid similar to nicotine. Alkaloids are organic compounds, derived from amino acids, that especially affect the nervous system.
Was Paracelsus right? Take arsenic, for example: We all know that arsenic is poisonous, yet we take in compounds of arsenic through the water we drink and the foods we eat, because it is a naturally occurring substance. Some research indicates that trace amounts of arsenic affect humans in positive ways. Scientists know that arsenic defi ciency stunts growth in chickens, rats, pigs, and goats.
In the past, arsenic compounds have been used as a remedy for everything from asthma to jealousy! Even in the early 20th century, an organic arsenic compound was used to treat syphilis until penicillin fortunately became available in the early 1940s.
Arsenic is now used to treat a rare kind of cancer.
Is there anything for which Paracelsus's "rule" doesn't work? Scientists think of botulin, produced by the bacterium Clostridium botulinum, as the most deadly poison known (1 gram evenly spread out and inhaled would kill more than a million people), yet doctors are now using botulin to erase wrinkles and to prevent migraines. The term hormesis refers to the concept promoted by Paracelsus: that substances that kill at high doses are actually benefi cial at low doses-the poison is in the dosage.

The Study of Poisons The History of Poisons
Prehistoric humans probably used poisons to kill their enemies. The earliest recorded use of poison was Socrates' execution in 339 BC with an extract of hemlock. During the European Renaissance, poisoning became an art, even an occupation or a hobby. Common poisons at the time came from plants such as hemlock, monkshood, belladonna, and toxic metal salts, with arsenic being by far the favorite. It left no trace, it was easy to get and use, and the symptoms looked like death by natural causes.
Forensic toxicology was developed in the 19th century. In 1814 Mathieu Orfi la published Traité des poisons, the fi rst systematic approach to the study of the chemistry of poisons. In 1836 a chemist named James Marsh developed a very sensitive and reliable test to detect arsenic in body tissues and fl uids. Most of the important alkaloids present in plants were isolated in the 1800s. Now, with modern analytical instruments, it is easier than ever to fi nd poisons, yet people still use them for murder and suicide.
As Paracelsus noted, dosage is an important part of toxicity, but other issues include (a) the chemical or physical form of the substance; (b) how it enters the body; (c) the body weight and physiological conditions of the victim, including age and sex; (d) the time period of exposure; and (e) whether other chemicals are present in the body or in the dose.
For example, arsenic is a metal, rather insoluble in stomach acid, and thus is not particularly poisonous. On the other hand, the compounds of arsenic trioxide (As 2 O 3 ) and arsenic pentoxide (As 2 O 5 ) are very poisonous. Arsenic can also be changed into a poisonous gas, arsine (AsH 3 ), which is used in the Marsh test.
We think of poisons as being swallowed, yet some substances are more toxic when injected, such as some recreational drugs. Other substances toxicology: the study of the

Elements of Toxicology
In 1840, the Marsh test came to popular attention in the trial of Marie Lafarge, charged with killing her husband, who died after eating a slice of her cake. Their maid swore that she had seen Marie adding a white powder to his drink, and it was shown that she had twice bought arsenic oxide from the local pharmacy, supposedly to kill rats at her husband's forge. Application of the Marsh test to his body showed no arsenic present, though it was detected in food in the Lafarge house. Mathieu Orfi la, appearing for the defense, claimed that the test was unreliable; however, when he himself applied the test to the body, he found arsenic. Marie was sentenced to life imprisonment. In 1852, suffering from tuberculosis, she was released by Napolean III, but she died that same year.
can be adsorbed through the skin, such as some particularly nasty chemical warfare agents. Inhaling many common industrial chemicals causes health problems; exposure is regulated by government agencies.
As you will learn in the next section on alcohol, blood alcohol content (BAC) depends directly on body weight and the sex of the individual. Stomach contents can also be important. Infants are more susceptible to toxins than adults, and old age can also weaken the body's ability to fi ght poisons.
The time period of exposure to toxins is very important. Let's use arsenic again as an example: Small amounts ingested over time will actually help in building up a tolerance for the poison. Larger amounts over time (chronic exposure) will cause medical problems such as weakness, sluggishness, hair and weight loss, mental instability, and skin and liver cancer. Acute toxicity refers to a dose large enough to cause immediate problems, including death.
The product information that comes with some antihistamines and sedatives clearly says that they should not be taken with alcohol, which would make the effects of both stronger. The combination of two chemicals can increase (causing synergism) or decrease (causing antagonism) their individual effects. Taking a chelating agent after swallowing an arsenic compound decreases the effects of both. The chelate "ties up" the arsenic before it can do its damage by reacting with the sulfi de linkages of enzymes. toxins: substances that cause injury to the health of a living thing on contact or absorption, typically by interacting with enzymes and receptors. The term is usually reserved for naturally produced substances that kill rapidly in small quantities. Over the years, scientists have developed ways to measure toxicity; however, because of the variables involved, there is no sure way to measure poison levels in humans, even using the results of accidental human poisonings. Instead, scientists use standardized animal toxicity tests, most often by feeding a chemical to rats or mice.
The term LD 50 (or lethal dose) refers to the amount of a substance that kills half the test population, usually within four hours. It is given in milligrams (mg) of substance per kilogram (kg) of body weight. LD 50 allows scientists to compare the toxicity of substances and even scale the amounts to different-sized animals. However, estimating lethal doses in humans based

Measuring Toxicity
A lady is lying in bed and she is dead. Beside the bed is a pool of liquid and two pieces of wood. How did she die? LD 50 : lethal dose for 50 percent of a given population Answer poison Popsicle on those for lab mice, rats, or rabbits is very uncertain because resistance can be so different among species. For example, nicotine kills humans at 0.9 mg/kg, but a lethal dose of nicotine in dogs is 9.2 mg/kg; in pigeons, 75 mg/kg; and in rats, 53 mg/kg.
In spite of the uncertainties, lethal dose values are all we have now.  The public's ignorance about the possible toxicity of tested drugs, environmental agents, and industrial chemicals has prompted the federal government to create regulatory agencies to ensure public safety: The Food and Drug Administration (FDA) deals with pharmaceuticals, food additives, and medical devices.
The Environmental Protection Agency (EPA) works on agricultural and industrial chemicals released into the environment.
The Consumer Product Safety Commission is concerned with toxins in consumer products.
The Department of Transportation (DOT) watches over the shipment of toxic chemicals.
The Occupational Safety and Health Administration (OSHA) is concerned with exposure to chemicals in the workplace.
OSHA's hazard communication program includes training, labeling, and issuing Material Safety Data Sheets (MSDS). These sheets include facts on the physical and chemical properties of a material and potential health hazards, as well as other information.
Let's review radioactivity in relation to the Litvinenko case study. Heavy elements, such as polonium, are unstable because they have too Clostridium botulinum is one of the most poisonous substances known to man. Some studies estimate an LD 50 for humans of 0.000001 mg/kg. If this is true, only a few hundred grams could theoretically kill every human on earth! Yet, it is used in BOTOX™ therapy. Injection of a dilute solution of botulin toxin has been used to treat neurological and muscular disorders, in cosmetic treatment of facial wrinkles, and for chronic and migraine headaches. Think of what Paracelsus said 500 years ago.
In December 2004, doctors confi rmed that Viktor Yushchenko, the Ukrainian presidential candidate running against the old-line Russian establishment, was suffering from dioxin poisoning. This isotope of dioxin (TCDD) is as toxic as ricin, so one drop of the pure substance would undoubtedly have killed him. Unlike ricin, however, the fat-soluble dioxin is more of a chronic poison; thus, he may have been fed small amounts of the material over time. Doctors found blood levels of dioxin 6,000 times higher than normal. One symptom of dioxin poisoning is the outbreak of facial cysts, which were quite evident in photographs of Yushchenko. TCDD was one of the contaminants found in Agent Orange, a chemical defoliant that caused many medical problems in Vietnam War veterans.
The dioxin referred to in Table 8 In a case where truth is stranger than fi ction, the poisoning of Aleksandr Litvinenko will long be remembered for the unusual and sophisticated method of killing. Litvinenko was a former lieutenant colonel in the Russian secret service (FSB, formerly the KGB) who defected and became a vocal critic of the Russian government. On November 1, 2006, he suddenly fell ill and was hospitalized.
He died three weeks later in a London hospital. The diagnosis was acute radiation syndrome caused by ingestion of polonium-210, a rare and highly radioactive isotope.
Investigation revealed that Litvinenko had met with two former KGB operatives earlier in the day. It so happens that traces of polonium-210 can be detected with a Geiger counter, so the path of this isotope could be traced. The evidence pointed to a teacup in a London hotel where Litvinenko had met with his former associates, Andrei Lugovoi and Dmitry Kovtun. Traces of radiation were found in many places, signifi cantly in several British Airways jets that had fl own from Moscow to London just before November 1 and a few days after November 1.
Andrei Lugovoi happened to have been on those fl ights.
Interestingly, others involved in this complex web of intrigue have been shot, have disappeared, or have suffered unexplained illness (including Dmitry Kovtun). No one has been arrested, and Russia will not allow extradition of Lugovoi to London to answer questions.
Theories, motives, and suspects abound, but Aleksandr Litvinenko is dead in a widely publicized, bizarre crime. many neutrons in their nucleus. They achieve stability by spontaneous decay, emitting any of three types of particles: Alpha (α) particle: a helium nucleus of 2 protons and 2 neutrons with a net positive charge of 2; heavy and slow, low penetrating power, stopped by a sheet of paper. Beta (β) particle: the same as an electron with a negative charge of 1, fast and light, more penetrating, stopped by a sheet of aluminum.
Gamma (γ) ray: a packet of energy with no mass or charge, very fast and energetic, high penetrating power, stopped by a thick sheet of lead.
Polonium is very rare. One of its isotopes, polonium-210 (210 refers to its atomic mass), has a half-life of 138 days; therefore, to make enough to kill a person, even at an estimated dosage of 1 microgram, requires a nuclear reactor. And even then, less than 3 percent would remain after two years because of its relatively short half-life.
Polonium-210 is strictly an α-emitter; thus, it could be carried around in the hand if one were foolish enough to do so. However, if taken internally, the α particles would cause massive cell damage. Indeed, the toxicity of polonium-210 is about the same as that of botulin.
Perhaps a polonium-210 salt such as a citrate or nitrate, dissolved in a small amount of water and carried in a glass vial (leaky?), was poured into Litvinenko's tea during that fateful meeting in the hotel.

Lead Poisoning
Lead compounds are not highly poisonous, but chronic exposure to lead poses a real health problem for many Americans, especially children, who are at far greater risk for lead poisoning than adults. The National Safety Council estimates that there are more than 400,000 children under the age of six who have higher-than-normal blood levels of lead, which can

Laboratory Activity 8.1, Advance Preparation
Obtain some paint fl akes; they don't need to contain lead because you can "dope" them by immersing some in lead acetate solution for an hour or even overnight. Remove and pat dry. The standard will be the "undoped" paint fl akes; the control, a dilute solution of lead acetate.
To make 0.1 M acetic acid, dilute the concentrated acid 1:170, or add about 0.6 ml concentrated acid to 100 ml water, or better, buy 0.1 M acetic acid.
To make 0.1 M sodium sulfi de solution, add 2.4 g to 100 ml water, or buy the solution already made up.
Any soluble lead salt will work as a control and for "doping. " Lead acetate works very well and is used in lab exercises in Chapter 6, "Fibers. " Dissolve a little in water.
lead to subtle brain damage, affecting memory and thought processes as measured, for example, by IQ tests.
The most common method of exposure is contact with lead-based paints. Before these were banned in 1978, lead was a common ingredient in paint. One of the strange properties of lead compounds is that they taste sweet, so a child teething on a windowsill, for example, will want more mouth contact. It is estimated that there are still more than 38 million houses in the United States that contain some leadbased paint. In 1992, the federal government passed a law requiring anyone selling an older house to certify that no known lead-based paint is present.
How can you know whether there is lead in paint? Two chemical properties are commonly used as a qualitative spot test: (1) the reaction of dissolved lead with sulfi de ion to form insoluble, brown-black lead sulfi de and (2) a reaction with an organic complexing agent, sodium rhodizonate, to make a characteristic pink color. Neither of these tests is specifi c to lead compounds, but it is unlikely that interfering substances in the paint will give a false positive.

Materials
The following activity will give you practice in checking paint for the presence of lead. For each investigative group of students:

SAFETY NOTE Also wear disposable laboratory gloves. Avoid inhalation, ingestion, and skin contact with chemicals.
! Lead-based paints are paints or other surface coatings that contain lead equal to or exceeding 1.0 milligram per square centimeter or 0.5 percent by weight or 5,000 parts per million (ppm) by weight.
You may want to have a class discussion of exposure to leaded products.

Procedure
Do not write in your textbook. Take notes in your science notebook. 1. Your teacher will give you several samples of paint flakes. Pick up a small piece (about 3 to 4 mm) with tweezers and put it in a small test tube. 2. Add 1-2 ml diluted acetic acid, and crush the mixture with a glass stirring rod to extract any leaded pigment. 3. Dilute 1:1 with distilled water, and add a drop or two of sodium sulfide solution. A brownblack precipitate shows the presence of lead. Run a standard (known to contain lead) and a control sample (contains no lead). What other substances could give a false positive? In Chapter 9 ("Trace Evidence"), you will use the formation of sulfides to make chromatographic separations of aluminum, cobalt, copper, nickel, and zinc visible. Anyone living in an older home may want to test the paint. If you wish to do so, be sure to collect a sample down to the wood base, because the prime or older coats are the ones most likely to contain the lead. Besides the sulfide precipitation test that you have already performed, you can make your own sulfide and rhodizonate test papers.

Procedure
To make your own lead detection test strips: 1. Sodium sulfide strips: Cut Whatman #1 filter paper into strips and soak them in 0.1 M Na 2 S for a few minutes. Dry in an oven set lower than 60؇C or overnight. Pressing a standard paint chip onto the paper that has been wet with the acetic acid should leave a black impression. Test also with the control sample. 2. Rhodizonate test strips: Immerse filter paper strips and dry. The solution is unstable, so make a lot of strips and store them in a dry place. A positive result for the presence of lead is from pink to purple, depending on the concentration of lead. Wet the paper first with the acetic acid to dissolve any lead.

Other Sources of Lead in the Everyday Environment
The ban on leaded gasoline in 1995 reduced a source of environmental lead, but tons still remain in our soils. Indeed, lead has been found in soil and dirt along highways and even in school playgrounds. In 1986, a nationwide ban restricted the use of lead pipes in homes, yet some towns still have older lead pipes carrying drinking water in their systems. This is not normally a problem because metallic lead is so insoluble, but if the water is acidic, lead can be leached from the metal. Solder joints in older houses contain lead. Lead crystal and some ceramics should not be used to store acidic food and drink.
Laboratory Activity 8.2, Procedure Notes, continued "Drugs." Searching the Web for those elements (with "test") will bring up lots of fancy analytical instrumentation and tests but should also show the Reinsch test, which is simple enough to carry out in a high school laboratory.
How should students physically carry out the test? Once they have fi gured out that they need standards, which they should realize by this point in their forensic careers, you can pull out the sets you have prepared. Steer them toward the use of small Erlenmeyer fl asks or beakers, using 20 to 30 ml of each solution.
What form of copper should be used? Wire is common, but foil or sheet works best. Should the solutions be heated? (Yes, boiling speeds up the process to just a few minutes.) How long should the copper be immersed? Let them work this out experimentally. Should the copper be cleaned fi rst? (Probably, with alcohol, to remove oil and grease that would interfere with the electroplating.) Should it be washed off after plating? (Defi nitely, because it has acid on it.) You can hope that the students have also opted to run the standards, or even one standard, before the sample for selecting the best experimental conditions. There is only so much autopsy sample. See if anyone thinks of running a control, that is, copper in only acid.

The Investigation of a Sudden Death
Here is a copy of the obituary of Dr. Albert Magnus. As is routine when the cause of death is not clear, and especially because he had seemed in such good health, an autopsy was performed.
Your lab has received a sample from Dr. Magnus's lungs with a request to look for a possible cause of death related to his work. What do you do?

Laboratory Activity 8.2
Reinsch test

Albert Magnus
Albert Magnus, age 54, died unexpectedly on August 14 at University Hospital. He was admitted to the hospital the day before, complaining of a continual cough and extreme shortness of breath. The diagnosis was pulmonary edema, but his condition advanced so rapidly and pervasively that he could not be saved. Dr. Magnus had just recently pioneered a novel method of gaseous doping of n-semiconductors for Zener diodes. He is survived by his wife of three years and two children from a previous marriage.
The quickest and simplest verifi cation of the method and results can be done by comparing data among the groups. Have each group take a picture of the plated copper, because its appearance will change.
If your students fi nd arsenic, then the source could have been at Dr. Magnus's workplace, but an arsenic-containing compound was also seen in his garage, as was a very poisonous form of mercury. However, if these materials had been fed to him, perhaps by a greedy wife, they would not have been found in his lungs. If either antimony or bismuth were found, work practices are likely to have caused his death. If the test came up negative, Magnus's death was probably natural-or was there something in the autopsy sample that masked the poison? (Adding a portion of each standard to the sample and then testing it would answer that question.) The Reinsch test leads beautifully into oxidation-reduction potentials. Demonstrate with a strip of metallic zinc immersed in a nice blue solution of copper sulfate; copper will plate onto the zinc as the blue color fades. Thus: Zn ϩ Cu ϩϩ → Zn ϩϩ ϩ Cu Cu ϩϩ ϩ 2e Ϫ → Cu reduction Zn → Zn ϩϩ ϩ 2e Ϫ oxidation Another example is the case of copper displacing mercury from solution: Hg ϩϩ ϩ Cu → Hg ϩ Cu ϩϩ which accounts for the nice, shiny mercury mirror on the copper in the Reinsch test. You can carry this as far as you want using the table of reduction potentials in a chemistry text. Unfortunately, the heavy group V metals are not included in most tables.

Advance Preparation
If you must purchase some, buy solid antimony potassium tartrate or a 0.1 M SbCl 3 solution (contact your Kendall/Hunt sales representative; also available from Flinn Scientifi c). Use only one heavy metal in the unknown; they mask each other.
For the demonstration: Prepare a 1 M solution of CuSO 4 . 5H 2 O, adding 25 g to 100 ml of water in a 250-ml beaker. Add a zinc strip and wait. Placing it on an overhead projector will allow the entire class to watch it.
For disposal: The copper plates can go in the trash. The acid solutions of the metals should be neutralized and the sulfi des precipitated with Na 2 S, dried, and placed in a plastic container (an empty fi lm canister is handy for this) for the trash.

Laboratory Activity 8.2, Procedure Notes, continued
Agents of the Bulgarian secret police assassinated Georgi Ivanov Markov in September 1978. Markov had defected to London from Bulgaria years before and was broadcasting programs critical of the Bulgarian regime.
On September 7, as Markov was waiting at a bus stop at Waterloo Bridge, he felt a sharp jab in his right thigh. He turned to see a man behind him with an umbrella, who apologized with a foreign accent. Markov thought nothing more of it, but the next morning he was admitted to the hospital with a high fever and vomiting. Despite being given massive amounts of antibiotics, Markov died three days later.
During an autopsy, examiners found in Markov's thigh a small platinum-iridium pellet, 1.7 mm in diameter, with two tiny holes precisely drilled at right angles to each other. The design of the pellet and the circumstances of Markov's death led investigators to believe that this was a poison pellet fi red by some device in the umbrella. Markov was a healthy, husky, six-foot-tall man, but the pellet could not have contained much poison. No telltale metabolites were found in his body.
By a process of elimination, ricin became the suspected probable poison; the assassin used perhaps as little as 2 mg. Tests on a pig corroborated this assumption. Coincidentally, investigators learned that, in the previous year, another Bulgarian defector had been jabbed outside a Paris metro station. He had fallen ill but recovered. A surgeon extracted an identical pellet from his body. He had been jabbed in a muscle in his upper back, away from major blood vessels, which may be why he lived.

1.7mm
Materials copper wire: 16-to 20-gauge (strip from house wiring); better is a copper sheet cut into strips, six strips per group 50-ml beakers or Erlenmeyer fl asks hot plate 2 M HCl; dilute concentrated hydrochloric acid 1:5, in a fume hood, wearing safety goggles and disposable laboratory gloves. Each investigative group will use 30 ml acid for each standard, the unknown, and a control, so make up 200 ml per group.
Standard solutions of HgCl 2 , As 2 O 3 , SbCl 3 , BiCl 3 in 2 M HCl. This is a very sensitive test; the amount of material you could fi t on a pinhead would be adequate for a single sample of 30 ml. Weigh out about 0.01 g of each for 250 ml acid. The antimony chloride (SbCl 3 ) is hygroscopic and may have turned to a liquid; if so, just use a few drops.

Laboratory Activity 8.2, Procedure Notes, continued
Consider how sophisticated poisoning has become since the days of Marie Lafarge, yet the evidence can still be discovered even if the culprit(s) cannot be apprehended. How many deaths from "natural causes" do you suppose are really the result of poisoning? Alcohol (ethanol, ethyl alcohol) is the most abused drug in America. In the United States, about 40 percent of all traffic deaths are alcohol-related-16,885 in 2005 (and more than two million accidents)! This has been the justification for and focus of our DUI laws.
Ethanol, like all alcohols, is toxic. Its principal effect is on the central nervous system (CNS), especially the brain. Alcohol starts circulating in the bloodstream throughout the body almost immediately after consumption. The rate of absorption into the blood depends on the amount of alcohol drunk, the alcohol content of the beverage, how quickly it was drunk, and the quantity and type of food present in the stomach.
The law is concerned with the amount of ethyl alcohol in the blood (blood alcohol content, BAC), expressed as percent weight per volume. Many studies have related BAC to brain functions and behavioral symptoms, providing a basis for the legal limits of intoxication. At present, the limit is 0.08 percent; this means that there would be 0.08 grams of pure alcohol for every 100 ml of blood in your body. In July 2005 Minnesota became the last state in the United States to lower the BAC limit to 0.08 percent.
The body starts to detoxify alcohol almost immediately on drinking (see Figure 8.1, sometimes referred to as the Widmark curve). The average rate of removal is 0.015 BAC per hour, but this can vary quite a bit.
About 90 percent of alcohol is chemically processed (metabolized) in the liver; it is   MA NTE O, NC-A wai tres s with a hist ory of drun k driv ing was con vict ed of seco nddeg ree mur der in the dea ths of four teen age rs in a 199 9 car coll ision . Mel issa Mar vin, 30, lear ned Satu rday that she may spe nd the rest of her life in jail, as a Nor th Caro lina judg e sen tenc ed her to at leas t 60 yea rs in pris on. A cou rt-o rder ed bloo d test two hou rs afte r the acci den t indi cate d a bloo d alco hol con tent of .21, putt ing it at an esti mat ed .28 at the tim e of the cras h. Juro rs deli bera ted for slig htly mor e than thre e hou rs Frid ay befo re retu rnin g thei r verd ict. In add ition to the seco nddeg ree mur der con vict ion, Mar vin was foun d guil ty of assa ult with a dea dly wea pon . Is it all right for him to drive home? No; although he is not legally drunk, his reactions and perceptions have been distorted so that he would be considered a hazard.
About 5 percent of the ethanol leaves the body unchanged in breath, perspiration, and urine. The concentration in breath is proportional to that in the blood, according to Henry's law. This law is the scientifi c basis of breath test instruments. The distribution of alcohol between blood and air expelled deeply from the lungs has been experimentally set at 1 to 2,100. Thus, 1 milliliter of blood will contain the same amount of alcohol as 2,100 milliliters of breath. Rather than having blood drawn as soon as possible after a driver is pulled over on suspicion of intoxication, the offi cer can quickly give a breath test. Blood, sampled under appropriate hygienic conditions, is preserved with an anticoagulant and sodium fl uoride and kept cold until it can be analyzed by gas chromatography.
Henry's Law is the concentration of gas in solution, Cg, which is proportional to the partial pressure of the gas over the solution, Pg; k is the proportionality constant: C g ϭ kP g Laboratory Activity 8.3

DR UN KE N DR IV ER IS NO T GI VE N TH E DE AT H PE NA LT Y IN FI RS T-DE GR EE M UR DE R CO NV IC TI ON
WIN STO N-S ALE M, NC-Tho mas Jon es, 40, who had two prio r con vict ions and a third cha rge pen ding for driv ing whi le imp aire d, was foun d guil ty of mur der and sen tenc ed to life in pris on. Two 19yea r-ol d wom en wer e kille d whe n Jon es's car stru ck thei rs. Jon es was not lega lly drun k but adm itted drin king two qua rts of bee r and taki ng pain kille rs befo re the cras h. The pain kille r bott le clea rly stat ed that the pati ent sho uld not drin k or driv e whi le taki ng the pills .
abs trac ted from ww w.d ui.
com /dru nk_ driv ing_ rese arch / dui_ offe nde r.htm l The following activity will give you practice in giving and evaluating breath tests to measure blood alcohol content.

Procedure
Do not write in your textbook. Take notes in your science notebook.

Teacher Note
A quantitative determination of "breath alcohol" can be carried out using a Spec 20-type spectrophotometer or a CBL and colorimeter. The students, however, are working with potentially nasty chemicals that have an even worse reputation. The basis of the analysis is given above; the concept of using spectroscopy is described in previous chapters; no new pedagogy is introduced. However, if you want the students to perform the experiment, directions can be obtained from the Web; for example, http://onsager.bd.psu. edu/~jircitano/chem2alcohol. pdf#searchϭ'experiment%20bre ath%20%20dichromate'.

Teacher Note
These activities are a nice example of an oxidationreduction reaction with a practical aspect. Small, disposable breath-alcohol tubes are now being sold to the public. Breathing into one changes the color from orange to blue-green. Science, like life, is a great circle. These simple no-tech devices rely upon the dichromatechromate(III) color change.
2. To make disposable indicator sticks, try this: Soak overnight about 5 g of silica gel (the kind used in thin-layer chromatography works well) in 20 ml of 0.1 M potassium dichromate (2 g/100 ml H 2 O), 2 drops of 0.1 M silver nitrate catalyst (1.7 g/100 ml H 2 O), and 10 ml of 6 M sulfuric acid. Filter and air-dry the yellow-colored crystals of silica gel. Cut the tip off a Pasteur pipette and push a small wad of cotton to the bottom. Pour the silica gel in and anchor it with another wad of cotton. Release the alcohol breath of the balloon into your detector. Brainstorm with the rest of your class how to estimate its sensitivity. What would be the effect of mouthwash?
Occasionally, a sobriety test may be administered by an offi cer at the scene of a traffi c stop. This is equivalent to a presumptive or spot test. Standard actions involve walking a straight line, standing on one foot while counting, reciting the alphabet rapidly or counting from ten backwards, touching a fi nger to the nose, a nine-step heel-totoe and turn, and observation of a horizontal gaze nystagmus.
What is horizontal gaze nystagmus? Nystagmus refers to an involuntary twitching or jerking of the eyeball when attempting to follow an object with the eyes. It increases with the level of intoxication. An offi cer instructs the intoxicated suspect to hold his or her head steady and look straight ahead. He holds a pen about 12 inches from the person's face and moves it slowly to one side and then to the other on a 45-degree angle. An intoxicated person cannot follow the motion of the pen smoothly, and his or her eyeballs jerk as the pen is moved at an angle away from the face. The higher a person's blood alcohol, the sooner nystagmus occurs in the 45-degree arc and the more extreme it is at 45 degrees.

Current Breath-Testing Technology
The newer breath-testing instruments are based on instrumental techniques, such as infrared (IR) spectrophotometry. A narrow band of IR light, chosen because of its absorption by ethanol, passes through a breath sample chamber. Comparing input and output energy, alcohol concentration is calculated using the Beer-Lambert law, which defi nes the relationship between concentration and light absorption. (See Chapter 7, "Drugs," for more about IR spectroscopy.) Another device uses electrochemical fuel cell technology, which catalytically oxidizes ethanol to create a charge imbalance across a semiconductor. By calibrating the current to neutralize the charge, the tester can determine the amount of alcohol "fueling" the cell.

Modern Breathalyzer
Vertical gaze nystagmus occurs when the eyes are turned upward, and is an indicator of whether the subject is under the infl uence of inhalants, depressants, or several widely used drugs.
Try observing nystagmus with your classmates.

Man Eats Underwear to Beat Breathalyzer
An 18-year-old man tried to eat his underwear while sitting in the back of a police car in the hope that it would absorb the alcohol before he took a Breathalyzer test.
-abstracted from The Advocate Whatever works! This didn't. He had a BAC of 0.08.

Would Litvinenko have died if he had merely spilled tea laced with Po-210 on his shirt?
14. Would breath analyzers measure nonpotable alcohols or organic vapors, such as methanol or rubbing alcohol (isopropyl alcohol)? Explain.
15. It is not likely that a person gives off any nonalcoholic organic vapors-or is it? Do some research on medical conditions that might cause someone to emit organic vapors. How would this affect breath testing?
16. About how much total alcohol would you expect to fi nd in the blood of a 110-pound woman with a BAC of 0.04? 17. Calculate how much blood the woman above has in her body. Show your work.
18. What would be the BAC of a 136-pound woman who has consumed three vodka tonics (2 oz of vodka each, with the vodka at 80 proof) during her lunch hour? If she forgets the time and talks for two more hours with her friend without having another drink, what will her BAC be when she gets back to work? 19. A 165-pound man was involved in a car accident at 10 PM. His BAC was measured at the time at 0.08, which he said was impossible because he had had only two beers (pint size, 5 percent alcohol) just after work at 6 PM. How many beers did he actually have? 20. After preliminary observations, a suspect is not required to do anything once pulled over under suspicion of intoxication. The observations consist of erratic driving, staggering, slurred speech, odors associated with alcohol, and the like. Evidentiary tests require the suspect to do something, such as blow into a test device, give blood, stand on one leg, or walk a straight line. Do these tests infringe on a person's constitutional rights?
Answers, continued

13.
No; see answer to question 12.
14. Any organic reducing agent will react with dichromate. Organic compounds that absorb IR light in the same waveband as ethanol can be detected. An alcohol fuel cell will also run on similar organic substances. 15. Answers will vary. 16. about 0.05 oz or 1.5 ml or 1.2 g (d ϭ 0.8 g/cc) 17. BAC ϭ wt alcohol ϫ 100 vol blood vol blood ϭ wt alcohol ϫ 100 ϭ 120 ϭ 3 L BAC 0.04 3 L is low for a 110-pound woman (see p. 309 in Chapter 11, "Blood"), so we can see how uncertain the estimates are in calculating BAC. 18. a) 0.15 b) about 0.12 (loses 0.015 per hour; see p. 309)

19.
He would have had a BAC of 0.07 on leaving the bar if he had drunk only two beers. Four hours elapsed, accounting for a reduction in BAC of 4 ϫ 0.015, or 0.06, which when added to 0.08 equals a BAC of 0.14 when he left the bar. This is equivalent to consuming four beers. 20. Answers will vary but must be supported.